SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f6c63d95d6dcd93cb7734fdbcd6b4f2ec9fd745ec2f01937ecae7d25d7a8e377' 
  AND token = 'sr2k16fMDl1h53bo7hN33EOM1CGus3cgujACTnEAnpA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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