SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7275a336c4df7bddf61ba0ff96d505ec509320d74eaf9de312f082e5cc94043f' 
  AND token = 'bjQGlKLV6CCYDsYNRloOGR7kdoBEcqvQZpW5yjW+DPU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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