SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a0bdcc63efaad17f048a35a3ae6647a60269c9364b3a504cc823eefdd1ece8ef' 
  AND token = '0OOERnERB3r+n4i3fVDZoS4teVFCEljfqMssIZurRvQ=' 
  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"
    }
  }
}