SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '200e92f4bedcafba60c4751a4420b71b1b61cf37ee22c670cf32fcd427f69728' 
  AND token = 'K7/a7px9r8lcibZqLK7OueFBZ/pqFvhXDjL8wnPmRsg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00014

JSON explain

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