SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5c4605449d5d54ebbea409336412bfb4e85840c4311dc203459ec2adcb39cbb0' 
  AND token = 'f01QCe4vPZKN80lBSjjYrJCgiCgrFuc+1OlJgjkgwV4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}