SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '417eb4041f107513cca46c8da5f0cb21f6d5595eea40363cef53de4e002b2c66' 
  AND token = 'b3sbASgxIWo2ltWvif7ThehrmMzxKNKRy766x6oNWYs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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