SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e3eee6088519050d988634aa4ed8f0adf2d6195cad42dfc2cf8bdf2af2146d47' 
  AND token = 'FrP9ZbSXbYpECx+HnJJFCBP7uKSMZo4JigsgVB2qDTk=' 
  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"
    }
  }
}