SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '449a1b52532bbdcab27abfb649c4fd3ddb0a869ed97364ed17a6d30f5cdf182f' 
  AND token = 'HL87byHSdhNGmBeYrmk7zrosdjHlpru2iyPwcGk/kB4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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