SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c2ecdbaeec13ed282155015ec55111b6cfd98931195b4e4cfa4327586a95b251' 
  AND token = 'LM94fw4FRyJXbnATY8FL9PRMFzW5c5wvgI8Ezd4pJTI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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