SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '644b7a04b254699668dc59ceadfcb96fab05e496ee54ffaeda17432136eb918f' 
  AND token = 'vE7MEaGNZHIpI3YE1EU9j8SH5LWP2HWdrztxfvmoxmk=' 
  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"
    }
  }
}