SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8f0e76d41bea35ede5eb7c011b93722cc877696a69930b5ac0e214c97ef1730a' 
  AND token = 'VJW5WaGWhvg+XuuPYZu0B1LfGqfyUzYBfYpv0lag7c0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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