SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a0186f8e75837c84235c615130d93d014905d51faf9a7f58e0a57412a4f1109a' 
  AND token = 'jl2YvXkGUXaHC/p4lBuwXAOKvtsu4Az2MoCl+fSEa2o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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