SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f04576dd521cb2e7023e47913016a9b0fd8d41261491ef9f095d2d4a64d25d24' 
  AND token = 'AjKBMWrP0/YvEP66hQzKbexHJKlseo29i3q52q4Pymg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00053

JSON explain

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