SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dffdfbfcfcbfc7b9d3822d1617ebe3624052ee4316be421a2ab8a59878a8eebe' 
  AND token = 'AKYINowLKb6BIJ1+BOPGuAD5FciN+bxz9JGR1QX8e2Y=' 
  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"
    }
  }
}