SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '72353512045985cf300c4053077ded186c61ed77d15b4968b4e12bda11295554' 
  AND token = '0H6Hzt9Tp2jaVBQietoIJpcU3KsYWILErSQeeKZuZn8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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