SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b3446014d860ac5ac71238af44f5ef2775c6080b182e6eb54a1e84666821d60e' 
  AND token = 'RRQesCs9ShY5rmccRKoQWoH7zQOByborNqAlSkRVMc0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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