SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5d30cc6d235ad76cb248e54d3af1a2e624681e6bcc72ac9fc56f27b637b25315' 
  AND token = 'NvsRGKF+QbtkFTKrNmATLYnkaRkymFvs3NokguO4qnQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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