SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f7239cd266515ea76abe903bd4cdbf547b62c3a5affbded979369f893eede625' 
  AND token = 'IAl/jd1gCto12YAg0DGKDmFXIRxW7U+acHoO178hCvI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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