SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dc4724ced8797cba132a7f01755d9143dba9b78819d25593c6ef08922da9548d' 
  AND token = 'n5O0Wi8W5wgTtPd0uxjcQThWvUcrQz1cCCiw8pKZTgI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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