SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f6726e3a24c5cec0e23a4769b3d2e4eb39427ee355e9728f0f35c9a9ceea2919' 
  AND token = 'Qi0f4g4dFYxKfTpE7LllL00V6ROWORgeUzyESBEVwko=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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