SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '81b13161925f52f40d4f0aa6c3ac1eb9e9689201a8b07071c739d002968df1ab' 
  AND token = 'soK2AjYSvieEWJWnBvor6S1S1KrjWDDbdI3e0FKTZJU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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