SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd4e610b2ea41845d60ac1eab87fc4d531871747c9f829f4accbad942245b1c98' 
  AND token = 'uO0eXh9QeRDAmpkxbjhMRA/N2w1hWYml6iGHeqvINPA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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