SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a11cedb65c74b279f33bfdbb9eb025538a64060fda13b9a95550308e13f9048f' 
  AND token = 'QudN8eOMbcVsFJUX8kwmihRi0BbbM1afRiS8ev4gW7g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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