SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '878b705ddaf5253599710e0a3683f66bd2a27dd404264994b65b92f5d74e0cf2' 
  AND token = 'oVW4jw/V8w374nou1zv7zF+guVcJeEGZ4Gmvsldvqw4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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