SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2efc57650bc7c6d855b73d86d701af5f8961b959fe76f7c18d00c93986d2c836' 
  AND token = 'HkJmaZp3FMhJRA20+dDtYY85z2AFSbnndN9wYDywyGc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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