SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1f73323950d1c38c0f8e8b2ceeb214956181e967a32b6c98d34052fb9f624b92' 
  AND token = 'AwtY8Xro7g4dSJ7xnR0uGjWEFOD+2TqIyMcCz3zwIuQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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