SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5f5c2ba7a49e558890398ab47f21a1f702db718ce34212bf739fd24d3f139932' 
  AND token = 'C7gJaD0lfoeAg7xQ3QunPFUTeaFzLZ4s+CwfqAKSW38=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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