SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9c7cdbd9e5648451592f03177eb373f9990a3cb06909fd7d2f2404047091e90f' 
  AND token = 'RqKmeQEaN3S2fjyAXapxR0yCdlQzv23zfMKCLEmR2Tc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}