SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8b660bbd7965571ee05a54c136750f3fe2bbb5a1b2d6447fe341aedf354a7416' 
  AND token = 'OrbNhwl5FbUvmnmNoQtKiPzFLi5Vdx7JpifKKpxRfa8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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