SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6ffe9ef14d3c9347358999147a0ea3282b852eef506a666ea74c1305c3815fe3' 
  AND token = 'dG9Zx7bJzltBKkOgy/j/PYGmUk4gxb6NL3qf4R6m2rQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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