SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2a6a6f4e2cfbb5d4870408755ba4af40386300f73ab4b774a5429286ee6db329' 
  AND token = 'B0dTdwziSXFa6uqgUpGymUI5f9HukWEFVvUWHb+7WBQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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