SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1388cc2321c2615bbdebb613dd0e1d03d5dc5bfaf5572e6aada0d8fded9764e5' 
  AND token = 'GgJqV/CkpLqWtQTlz7qzQkMBm/4DxPcsDUwYV0OH42s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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