SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9a997f95d8e281523dd793f8ee6e3f23edf5ca64bdaaf141298d31c442c6b715' 
  AND token = 'hKO8/i53cLl9e8hUbKh6UL24k6aq8zKfULAYRy/LPgs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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