SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bfb39a78651cf412b457b71516986f99493478f5175f0f29a2b652abcd7344c9' 
  AND token = '1OaP3g9OhvDWzHGMYlk4oXpmv4aO0mXJf0Lx4vuQijg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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