SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '71bf65240caf9b5c59a4743f041505dfb01054cff84ee83b596ac299eb6d636e' 
  AND token = '999k+jXHAUCNVFGA0fsrVjExM+lmcWQ2LecHyvfmNpI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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