SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3caf19839e2ffb953ef0773cfd4c244dea48aca387bf5a5ba8208465b5b92a48' 
  AND token = 'f552WKuQKOtq0yi4wvXvhwjcSRY8N7Y5dy6YQKYQyao=' 
  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"
    }
  }
}