SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'ab6568f2a33960b08cdfbb79b00b31898cd2ec9ab9de911e53a84f0aaf0e9b9c' 
  AND token = 'U6XbBpS9OIR5uzGICZdbR1e4nBnIKkov+B/V0hFE5dM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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