SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6f09165a493936103822ea4e9055218898ce3a502ea9cb362e9022dec91552b3' 
  AND token = 'e5jLrLHLsmlxNEkNK2UVpPWGZ9L4KgQUK2TrAj4wRus=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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