SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '976fbdb4419755e89203a7bbf776b457fbe94993a983a9cbdb48c222f62a5ad6' 
  AND token = 'vNGKxdJciHwduy9Pi8sug3wDHM64yTilPtVDBTjCAgQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}