SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '34aec413fec44c674f85d2ac89dfad441fc4cccdca59a9913f96be9717e07a2e' 
  AND token = '6sAfQZKXjtiMs4n8XopD9RD1YYILqLApWWnuFnl4Ams=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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