SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6abc03e6a424b8fed6963ae3e670fc9fcf0af81ae9f4d082327ed71a332d5d7e' 
  AND token = 'mObAZyFa0hnqsyyqhvWbp9YAuUPNGezQpouzuXaN8CQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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