SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e62701a25a422db4e27a013e582a2eeb34fc118998433f686976eea7ef311573' 
  AND token = 'kq1oQnMcKXkvqh3BhsSpLV4n2XQnzW3jBzy5Z5dYwzg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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