SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '87c7481d8ac2d5ccb6e5569e9ccebe68ac7534c0eb92a843b8f2278f35acd346' 
  AND token = 'lZ64A+mjvcE+Bb1VktrxGrmpf9sT0lbX8KL5ba2Xl0Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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