SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9e1ad88db7c60940094c412d93c3129f996a784d02048028d219a9a8961bfd6a' 
  AND token = 'hlccNaU50+jOFzhXWjzzpSU+a9khCYx3veTfEqgETKQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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