SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c16af817437058e0709ca97121e55919ec6e0f1f28a2f5fcbb0f759c9e0028a9' 
  AND token = 'Nm0KJ8MVSWFEpM0N4x4bOIStiYEft5iErZgsFLUranc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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