SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f235ad460a46dafaaf93cf983e50aa00a462355798d2a9880a39f771050054d6' 
  AND token = 'hIDiiZc4NciHLebiZZoMpC+4fne3TxAfPk522HjPu24=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}