SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ac826c57aa90d402b50db4eb455d90352ec4f77fd907c318c11f5721245e8ed4' 
  AND token = 'mSmglwmXW7TIRvEWmZJ5EaGUnqwIqH+rYMSbXB5QVB0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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