SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2f5d077a1c6e5406c31a1d682aca7fed766bf07c892b0df09899236b95fe5612' 
  AND token = 'vJA4jQpjvutBBurwRZSdqBW8bj2Gd8lni9U0nsO9i9w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00010

JSON explain

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