SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cc885653a4dbd402611cefcab45d4f8a549e1719f32bdd32d978a42d1fa46a23' 
  AND token = '6WEYFrLaQ88hZ3Qi36nT1KyAot2CsEkrxtnxjLVl70o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}