SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5264b91d221ea61e2214bccca25a2b3f8c34aa39a91eebed7b0d7f13f6cc5889' 
  AND token = 'bLa59lQIMFNeDtGmylLAaBwatNpB2Ui5CIg1z7/FJMM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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