SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '71a73928d1b1f972ecf36ef6e584765762dc537acb468b5c6199bc94e48277ef' 
  AND token = 'UgfoTAx+ul+ozZtR/p89ymCpHt5BFJDOk/vPI8DQbwg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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