SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6a38b07acf6ecf208988b27f55cc1d90555bde9996b3de8495462a2c050c8dea' 
  AND token = 'jwPe85xhO56qar6rAVeqs5jr/j7zfpAt3GpSVcWeB4k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00070

JSON explain

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