SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '17ba617fa025bdcb2dcc6498ed4973edb5b88949d1b310ec5b07a75387a95e10' 
  AND token = '60lHi/4pJXZGCjkhb9RO0rd830zvbAi9aqFkftQn6AQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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