SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a74c6e89eb05d3e31bbd18ba648002613d5fbb69f0b9d386463247ff953a6744' 
  AND token = 'pIehpObmFXrKGfmzq0HCo4WviEKxvw9oYwRCH+ARReQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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