SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3751c63ac6efc555596ebb8e7a7a5a874698b35e80730cfc055c0045291bcd3a' 
  AND token = 'kZcgZaNNIz175mBUEdMuPTiSiIcbzY4WGUVJVYIy2Vg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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