SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fbe8d1d897a1ac1089bafd5b6aa6471117da9ac88a21e894ad9e1d77cfcce643' 
  AND token = 'QF/lKuDBj0hDWdV4INCqlkid10ag0UXs2AQecrXIyDM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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